Retrieves the first non-loopback IP address, (i.e., filters out 127.0.0.1 addresses) for machine your are running on. - Java Network

Java examples for Network:IP Address

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Description

Retrieves the first non-loopback IP address, (i.e., filters out 127.0.0.1 addresses) for machine your are running on.

Demo Code

/**//from  ww  w. j  a va2  s.  c  om
 * Copyright (c) Codice Foundation
 * 
 * This is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser
 * General Public License as published by the Free Software Foundation, either version 3 of the
 * License, or any later version.
 * 
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details. A copy of the GNU Lesser General Public License
 * is distributed along with this program and can be found at
 * <http://www.gnu.org/licenses/lgpl.html>.
 * 
 **/
//package com.java2s;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.util.Enumeration;

public class Main {
    public static void main(String[] argv) throws Exception {
        System.out.println(getFirstNonLoopbackAddress());
    }

    /**
     * Retrieves the first non-loopback IP address, (i.e., filters out 127.0.0.1 addresses) for
     * machine your are running on.
     * 
     * @return
     * @throws SocketException
     */
    public static InetAddress getFirstNonLoopbackAddress()
            throws SocketException {
        return getFirstNonLoopbackAddress(true, false);
    }

    /**
     * @param preferIpv4
     * @param preferIPv6
     * @return
     * @throws SocketException
     */
    public static InetAddress getFirstNonLoopbackAddress(
            boolean preferIpv4, boolean preferIPv6) throws SocketException {
        Enumeration en = NetworkInterface.getNetworkInterfaces();
        while (en.hasMoreElements()) {
            NetworkInterface i = (NetworkInterface) en.nextElement();
            for (Enumeration en2 = i.getInetAddresses(); en2
                    .hasMoreElements();) {
                InetAddress addr = (InetAddress) en2.nextElement();
                if (!addr.isLoopbackAddress()) {
                    if (addr instanceof Inet4Address) {
                        if (preferIPv6) {
                            continue;
                        }
                        return addr;
                    }
                    if (addr instanceof Inet6Address) {
                        if (preferIpv4) {
                            continue;
                        }
                        return addr;
                    }
                }
            }
        }
        return null;
    }
}

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